As have been confirmed, the genetic polymorphisms of NHEJ repair genes can modulate the RILI risk in non-small cell lung cancer (NSCLC) patients under radiotherapy treatment; for example, the loss or hypomorphic mutations of LIG4 can contribute to increased radiosensitivity and cause LIG4 syndrome, a disease with many characters including pronounced radiosensitivity and malignancy [15, 16]. The gene discussed is LIG4; the disease is non-small cell lung carcinoma.